All control surfaces are totally sealed to the flying surfaces with no gap between them by custom hinging. All gear doors function and seal up the landing gear holes.

Flight surfaces are sheeted, glassed and the aircraft is painted with "PPG" automotive paint.

Now this aircraft is over TEN years old. I would guess I have somewhere in the neighborhood of 50 flights on it.

And this is one hell of a flying aircraft. Capable of doing any maneuver you want to do with it. Due to it's design and how sleek it is, it is not effected by wind much. The take offs and landings are a thing to see. Amazing and smooth.

OK here is the rub and what I am totally at a loss to figure out:

I am at the flying field a couple weeks ago. I install a new "HRB", 6000mah, 4 cell battery in the aircraft and make a flight. The flight is just like all the others have been. Beautiful !!

About twenty minutes later I am going to make another flight and install another new battery. Check all control movements and even cycle the retracts.

It taxi's fine and runs down the runway and rotates.

From there it goes crazy. It is all over the sky. It is responding to input but not correctly. It is so bad that before I know it, it is in the ground and it is not pretty.

What in the hell went wrong? Why did it do this? Nothing has changed from the first flight which was so nice.

I was unable to retrieve the Lipo from the crash site. Looked all over but never found it in this thick soy been field. The receiver and radio is still functioning.

So here I am trying to figure out what happened. I never had any control over it .

I am thinking radio problems. I am thinking transmitter failure.

I call Spektrum, then do a repair request form and send the transmitter and receiver to them.

They find nothing wrong with the radio gear.

That is really disappointing to me. I can't find any thing to blame this crazy flight on. I have no clue what happened. I can't even blame it on pilot error.

Any advise or suggestions from you modelers would be greatly appreciated. Have any of you ever experienced anything like this?

BTW: Nice thing about making your fuselage out of fiberglass. I have the plug laying around the shop and both wings and the tail section survived the crash. So I am building another.

Nice bird! Im a newbie, I have a buddy warn me about spectrum radios, he said he had an issue with his and it tore up a good bird also? Since he said that the bird im building may not get a spectrum install but perhaps another brand. I cant take chances with inferior products, this hobby like others is expensive, and im trying to stretch a dollar....

Hello, awesome looking airplane. I hope it goes back together like the first one. I lost control of my electrified glider the other day. It went straight and steady for about 15 seconds. I turned the transmitter off and then back on and regained control. It is a Spectrum DX6i. I have been trying to figure out what went wrong. I am thinking it is the ESC. But now I hear you have a problem with Spektrum, and I hear that you said someone else has warned you about Spectrum. I talked to a person at Esprit Tech about the ESC, a Spin Pro 66. He said there could be microwave interference at the field I was at. I have never heard that before. This is the third time at this field. The plane flew perfectly at a different field yesterday. The transmitter passed a range check. If it is the transmitter, what would be a better one? It would have to be a 6 channel. I also can't afford to lose my aircraft. It is large (9 servos) and expensive.

I hate these situations, as one may never know what the failure was caused by.
Spektrum radios are generally very solid, so especially after having been checked out, are much lower on the list for potential failure.
George didn't mention what he had set up for failsafe, but whatever version usually will result in the plane following some predetermined path (like louisthelou mentioned), and not going crazy. Failsafe kicks in when the receiver can't hear a signal - either due to receiver antenna being blocked by something (metal, carbon fibre in the fuselage) or due to overwhelming interference (microwaves, etc.)
Going crazy speaks to intermittent control. It could be a bad ESC, dropping voltage to the receiver. It could be a bad battery (even if new). It likely could be a bad electrical connection - loose plug, poor solder joint, etc. Switches are the big culprits here. It could be the motor going bad, and the noise traveling over the servo wires. It could be a servo going bad, and doing the same thing.
All you can do is not trust anything. Replace what you can afford to replace. Test and retest the suspect items left over. Only use them in something you don't mind losing until you are confident they have proven themselves to be dependable.

Nice bird! Im a newbie, I have a buddy warn me about spectrum radios, he said he had an issue with his and it tore up a good bird also? Since he said that the bird im building may not get a spectrum install but perhaps another brand. I cant take chances with inferior products, this hobby like others is expensive, and im trying to stretch a dollar....

My too but my buddy told me that all the major brands can be subject to problems, especially user installation problems.

I thank all of you very much for your help and suggestions. Greatly appreciated.

I have made many flights with my Spectrum DX8 radio after Spectrum sent it back. I have had no problems at all. So I am thinking it was something else that caused the problem. I did notice on my "Tirawa" that the servo that operated the landing gear doors was motoring. Don't know if that was the problem or not. Just the only thing I found that showed any sign of not operating properly.

I have changed out almost everything in the new construction of the aircraft and hoping for the best.

Back in the 80's and 90's when I used to be somebody in this field, owning "Custom RC Aircraft" manufacturing a complete line of RC scale jets, attending about 10 to 15 different fan flies every year and also under contract with George Lucas of Industrial Light & Magic, one of my sponsors was "Airtronics" radios. I never had a single problem with their radios. So if I was to recommend any other radio than Spectrum, that would be where I would go.